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81.
二乙基二硫代氨甲酸银体系流动注射法测定砷 总被引:1,自引:0,他引:1
本文设计了一种AgDDC流动注射-分光光度法测定砷的系统。该系统采用自制的氢化物发生及吸装置,将液体流路和载气流路结合在一起。 相似文献
82.
A substoichiometric isotope dilution method was developed for the determination of microgram amounts of manganese. The method involves the use of carrier-free 54Mn with Mn(II) carrier and its complexation with 2-thenoyltrifluoroacetone (TTA) at pH 8.5, the complex then being extracted into isobutyl methyl ketone. A minimum of 50 ng of manganese can be determined. The method was applied to the determination of manganese in several standard reference materials and biological samples such as tea leaves, spices and condiments. The method is simple and fast and yields results with high accuracy and precision. 相似文献
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84.
The relativistic ground and low-lying excited state potential energy curves of AgH and AuH in the presence of a cylindrical
harmonic confining potential were calculated using the multi-state multi-reference perturbation theory with the spin-free
no-pair Hamiltonian obtained via the third-order Douglas–Kroll transformation, incorporated with the full two-electron Breit–Pauli
spin–orbit operator. The spectroscopic parameters were obtained for both the scalar- and quasi-relativistic potentials. The
spin–orbit coupling constants were calculated for several strengths of the confining potential, and the effects of the applied
potential on the coupling constants were analyzed using configuration interaction.
This paper is dedicated to Serafín Fraga—colleague, mentor, and friend. 相似文献
85.
Two novel heptadentate ligands, pentaaza macrocycles with two pendant xpyridyl and phenol groups, were prepared and the crystal structure of the manganese(II) complex of N,N′-bis(2-pyridylmethyl)-pentaaza macrocycle revealed a pentagonal bipyramidal geometry. 相似文献
86.
B. M. Bulychev V. N. Verbetskii A. I. Sizov T. M. Zvukova V. K. Genchel’ V. N. Fokin 《Russian Chemical Bulletin》2007,56(7):1305-1312
Crystallization of non-solvated aluminum hydride from a diethyl ether-benzene mixed solvent was studied. The desolvation of
AlH3·(Et2O)x etherate in solution and the crystallization of α-AlH3 during polythermal heating of the solution occur only in the presence of ≥10 wt.% LiAlH4. The process is multistage, and the crystallization begins with the formation of the AlH3·0.25Et2O solvate, which recrystallizes in the solid phase into γ-AlH3 and then α-AlH3. Four crystalline modifications of aluminum hydride were characterized by X-ray diffraction and electron microscopy.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1259–1265, July, 2007. 相似文献
87.
本文研究了Cp_2ZrH_2与丙烯酸和Cp_2Zr(H)Cl与丙烯酸钠、巴豆酸钠的反应。产物由IR 1~H和~(13)CNMR、ESR谱、气相色谱以及化学方法分析鉴定。产物水解得到与底物相应的饱和酸.用~1H NMR方法考察了Cp_2ZrH_2与丙烯酸的反应过程,用IR方法考察了Cp_2Zr(H)Cl与丙烯酸钠的反应过程。实验结果表明,上面两种反应首先消除H_2或NaCl,形成锆氧健,然后碳碳双键还原生成二茂锆羧酸盐配合物,其中羧酸根离子与二茂锆桥式双齿配位。 相似文献
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The Manganese(III)-based regioselective α′-keto radical generation of unsaturated ketones is a versatile synthetic procedure with broad applicability. The generated α′-keto radical slowly creates a metal enolate in a solvent at reflux. The resultant metal enolate affords the corresponding α′-allylated α,β-unsaturated ketones in good yields. This method is the first example of the metal mediated regioselective α′-allylation of α,β-unsaturated ketones. The ketones that have α or β-alkoxy groups also work efficiently. 相似文献